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At least 1,261 records · Page 70Linked to original sources
PubMed2003

Morphological characterization of different human cervical mucus types using light and scanning electron microscopy.

BACKGROUND: This study was conducted on human cervical mucus using light microscopy (LM) and scanning electron microscopy (SEM). The objective was the morphological characterization of the different mucus types, with samples taken from the lumen of the cervix and from the different secretory zones of the cervical mucosa. METHODS: A total of 230 samples from 195 women were spread out on slides and air dried. The phenomenon of 'ferning' was observed and assessed in these samples using both LM and SEM. Further samples from the lumen of the cervix and the different secretory crypts were spread out on cover slips and fixed with glutaraldehyde (2.5%) to be studied by SEM. RESULTS: The results show the presence of four different morphological mucus types, namely L, S, P and G, in both types of sample using dried and fixed techniques. CONCLUSIONS: Mucus from the lumen of the cervix appears to be a morphologically heterogeneous entity. It contains different types of secretions, the proportions of which vary throughout the menstrual cycle. The different mucosal types show different types of crystallization, different patterns of ultrastructure (probably related to the arrangement of the glycoprotein network) and are produced in different secretory zones of the crypts in the cervix.

Adult↗
PubMed1976

Light and scanning electron microscopy of exfoliated bladder epithelial cells in rats fed N-(4-(5-nitro-2-furyl)-2-thiazolyl)formamide.

Urine specimens obtained periodically from weanling male F344 rats fed 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for 25 weeks followed by control diet for an additional 35 weeks, were examined by light microscopy (LM) and scanning electron microscopy (SEM). LM revealed red blood cells and atypical transitional cells in the urine at 25 and 43 weeks, when microinvasive transitional cell carcinoma was present. Malignant transitional cells were seen in the urine by LM at 60 weeks, when muscle invasion was present in histologic sections. However, SEM showed pleomorphic microvilli on exfoliated urothelial cells as early as 10 weeks after the beginning of FANFT administration, and the microvilli became increasingly pleomorphic as the bladder lesions progressed to muscle invasion at 60 weeks. Noninvasive tumors were present in histologic sections of rat bladders examined at the end of 10 weeks of FANFT administration. The numerous microvilli on exfoliated bladder tumor cells were in sharp contrast to the peaked microridges of normal exfoliated superficial cells.

Animals↗
PubMed1975

Single atom image contrast: conventional dark-field and bright-field electron microscopy.

Single atom inage intensities are calculated for bright-field and various dark-field modes, including the ideal beam stop, a wire beam stop, tilted illumination and a displaced aperture. Comparisons of scattering amplitudes and elastic scattering cross-sections are made with different object potentials and scattering formulations. The image contrast for one mercury atom (Z equals 80) on a column of carbon atoms (Z equals 6) as the substrate is also discussed for both the bright-field and the various dark-field situations.

Carbon↗
PubMed1971

Observations by electron microscopy on pig muscle inoculated and incubated with Pseudomonas fragi.

Myofibrils from pig muscle inoculated and incubated with Pseudomonas fragi showed an extremely disrupted appearance as compared to uninoculated controls. There was an almost complete absence of material in the H zone, marked disruption of the A band (probably myosin), and some loss of dense material from the Z line. These changes indicated that marked proteolysis had occurred. Bacteria observed in spoiled muscle tissue exhibited protrusions or blebs on the outer surface of the cell walls. The blebs appeared to form detached globules that migrated into the muscle mass. Bacteria grown in non-muscle-containing media did not produce blebs, which indicates the blebs were induced by growth on muscle tissue. The possibility that the blebs and globules may contain a proteolytic enzyme responsible for myofibrillar disruption is discussed.

Animals↗
PubMed1996

Temporal analysis of the developing Chlamydia psittaci inclusion by use of fluorescence and electron microscopy.

The chlamydiae are obligate intracellular parasites that develop and multiply within a vacuole (termed an inclusion) that does not fuse with lysosomes. Inclusion morphology varies dramatically among the different chlamydiae, particularly within the species Chlamydia psittaci. Some strains develop within a single vacuole, while the mature inclusion of other strains consists of several distinct lobes, each filled with chlamydial developmental forms. The development of this lobed structure was investigated in HeLa cells infected with the guinea pig inclusion conjunctivitis (GPIC) strain of C. psittaci. We employed two recently described probes for the chlamydial inclusion to study the development of these unique lobed structures. The novel probes were an antiserum directed at a protein localized to the GPIC inclusion membrane (anti-IncA) and the fluorescent sphingolipid (N-[7-(4-nitrobenzo-2-oxa-1,3-)]) aminocaproyl sphingosine (NBD-ceramide). Lobed inclusions developed in cells infected at very low multiplicities of infection, suggesting that the structure is not a function of infection by more than one elementary body (EB). Double-label fluorescent-antibody analysis with anti-IncA and an antibody directed at a chlamydial outer membrane protein showed that, prior to 18 h postinfection (p.i.), the inclusion membrane and the chlamydial membrane were tightly associated. After 18 to 20 h p.i., the lobes began to expand and fill with developmental forms and the inclusion membrane and chlamydial membrane became distinct. At times from 8 to 48 h p.i., GPIC inclusions were shown to receive fluorescent derivatives of NBD-ceramide and to be localized to the perinuclear region of the host cell. Labeled lectins with affinity for carbohydrate moieties localized to the Golgi apparatus showed that the lobes of mature inclusions surround the Golgi apparatus. Labeling with NBD-ceramide and the Golgi apparatus-specific lectins therefore demonstrated a functional and physical association of the inclusion with the Golgi apparatus throughout the developmental cycle. Collectively, these results lead to a model for the development of the lobed chlamydial inclusion. We propose that the lobed structure is a result of division of inclusions occurring in parallel with the multiplication of reticulate bodies (RB) early in the developmental cycle. The division of inclusions slows or stops in mid-cycle, and dividing RB accumulate within the enlarging lobes. The RB then differentiate to EBs, the inclusion and cell are lysed, and EBs are freed to infect another cell.

Chlamydophila psittaci↗